The present invention relates to a new process for making polyarylene sulfides. These polymers are useful adhesives and thermoplastic molding resins and can also be intermediates for making infusible thermoset materials.
Aromatic sulfide resins have been made in the past by various methods including reacting a chlorinated benzene with sulfur and sodium sulfide (Macallum, U.S. Pat. No. 2,513,188) and by heating a metal salt of halothiophenol (Lenz et al., U.S. Pat. No. 3,274,165). These methods are effective but have various disadvantages such as expensive solvents, long reaction times, and difficult separation and purification procedures. More recently, a method has been described whereby sulfur monochloride was reacted with phenyl ether at a relatively low temperature to make a low molecular weight polymer containing both monosulfide and disulfide linkages (Fujisawa et al., J. Polymer Science (B), 8 (1) 19-24 (1970). Polymers containing disulfide linkages are undesirable because the disulfide groups are subject to oxidative degradation and the polymers are thermally unstable.